Method and apparatus for effectively providing tdd configuration information to user equipment and determining uplink transmission timing in mobile communication system supporting tdd

ABSTRACT

A method for configuring a time division duplex (TDD) of a user equipment in a communication system, according to one embodiment of the present invention, comprises the steps of: receiving from a base station a first TDD configuration; receiving from the base station a message including information related to a dynamic TDD configuration; receiving a second TDD configuration according to the received information related to the dynamic TDD configuration; receiving from the base station an uplink grant; and determining whether to apply the first TDD configuration or the second TDD configuration based on a method by which the unlink grant is received. According to one embodiment of the present invention, the advantages of configuring a shorter cycle of the TDD to the user equipment supporting the TDD in a wireless communication system, and rapidly configuring the TDD to the user equipment variably according to a communication situation are provided.

TECHNICAL FIELD

The present invention relates to a method and apparatus for providing aUser Equipment with TDD configuration information effectively anddetermining uplink transmission timing in a mobile communication systemsupporting TDD.

BACKGROUND ART

Mobile communication systems were developed to provide mobile users withcommunication services. With the rapid advance of technologies, themobile communication systems have evolved to the level capable ofproviding high speed data communication service beyond the earlyvoice-oriented services.

Recently, standardization for a Long Term Evolution (LTE) system, as oneof the next-generation mobile communication systems, is underway in the3^(rd) Generation Partnership Project (3GPP). LTE is a technologydesigned to provide high speed packet-based communication of up to 100Mbps and aims at commercial deployment around 2010 timeframe. In orderto accomplish the aim, a discussion is being held on several schemes,e.g. reducing the number of nodes located in a communication path bysimplifying a configuration of the network and maximally approximatingwireless protocols to wireless channels.

Meanwhile, unlike voice service, the data service is provided on theresource determined according to the data amount to be transmitted andchannel condition. Accordingly, the wireless communication system,especially cellular communication, is provided with a scheduler whichmanages transmission resource allocation in consideration of therequired resource amount, channel condition, data amount, etc. This isthe fact in the LTE system as the next generation mobile communicationsystem, and the scheduler located at the base station manages thetransmission resource allocation.

Recent studies are focused on the LTE-Advanced (LTE-A) for improvingdata rate with the adoption of various new techniques to legacy LTEsystem. Interference Mitigation and Traffic Adaptation (IMTA) is one ofthe techniques being studied for use in the LTE-A system. The IMTA is atechnique of changing the ratio between uplink and downlink resourceallocation amounts at a short cycle for controlling the uplink anddownlink traffics and interference amounts in TDD mode. In order toimplement the IMTA technique efficiently, it is necessary to improve theLTE-A system in various respects.

DISCLOSURE OF INVENTION Technical Problem

The present invention has been proposed to solve the above problem andaims to provide a base station and a user equipment configuring TDD modeof the terminal variably and operation methods of the user equipment andbase station in a wireless communication system supporting Time DivisionDuplex (TDD).

Solution to Problem

In order to achieve the above objects, a Time Division Duplex (TDD)configuration method of a terminal in a communication system accordingto an embodiment of the present invention includes receiving a first TDDconfiguration from a base station, receiving a message including adynamic TDD configuration information from the base station, receiving asecond TDD configuration according to the received dynamic TDDconfiguration information, receiving an uplink grant from the basestation, and determining to apply one of the first and second TDDconfigurations based on a method in which the uplink grant is received.

A terminal of configuring Time Division Duplex (TDD) in a communicationsystem according to another embodiment of the present invention includesa transceiver which receives a first TDD configuration from a basestation, receives a message including a dynamic TDD configurationinformation from the base station, receives a second TDD configurationaccording to the received dynamic TDD configuration information, andreceives an uplink grant from the base station and a controller whichdetermines to apply one of the first and second TDD configurations basedon a method in which the uplink grant is received.

A Time Division Duplex (TDD) configuration method of a base station in acommunication system according to another embodiment of the presentinvention includes transmitting a first TDD configuration to a terminal,receiving a message including TDD configuration capability from theterminal, determining whether to configure dynamic TDD operation basedon the received message, transmitting a message including dynamic TDDconfiguration information to the terminal according to the determinationresult, transmitting a second TDD configuration according to the dynamicTDD configuration information, and transmitting an uplink grantaccording to one of the first and second TDD configuration.

A base station of configuring Time Division Duplex (TDD) of a terminalin a communication system according to still another embodiment of thepresent invention includes a transceiver which transmits a first TDDconfiguration to the terminal and receives a message including TDDconfiguration capability from the terminal and a controller whichdetermines whether to configure dynamic TDD operation based on thereceived message, wherein the transceiver transmits a second TDDconfiguration according to the dynamic TDD configuration information andtransmits an uplink grant according to one of the first and second TDDconfigurations, and the terminal applies one of the first and second TDDconfigurations based on a method in which the uplink grant is received.

Advantageous Effects of Invention

The method and apparatus according to an embodiment of the presentinvention is advantageous in terms of allowing for configuring arelatively short TDD cycle to the user equipment and configuring TDD tothe user equipment dynamically in adaptation to the communicationcondition.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating the architecture of an LTE system towhich the present invention is applied;

FIG. 2 is a diagram illustrating a protocol stack of the LTE system towhich the present invention is applied;

FIG. 3 is a diagram for explaining a modification period in a normal SIBtransmission method;

FIG. 4 is a signal flow diagram illustrating a normal SIB transmissionmethod;

FIG. 5 is a diagram for explaining a normal SIB scheduling method;

FIG. 6 is a signal flow diagram illustrating the embodiment 1;

FIG. 7 is a flowchart illustrating the UE operation in the embodiment 1;

FIG. 8 is a flowchart illustrating the eNB operation in the embodiment1;

FIG. 9 is a signal flow diagram of embodiment 2;

FIG. 10 is a flowchart illustrating the UE operation in the embodiment2;

FIG. 11 is a flowchart illustrating the eNB operation in the embodiment2;

FIG. 12 is a block diagram illustrating a configuration of the UE towhich the present invention is applied;

FIG. 13 is a block diagram illustrating a configuration of an eNBaccording to the present invention;

FIG. 14 is a diagram for explaining a TDD frame structure;

FIG. 15 is a diagram for explaining the PagingCycle-dynamic-TDD andi_s-dynamic-TDD information;

FIG. 16 is a flowchart illustrating a UE operation of determining asubframe for uplink transmission by applying the first and second TDDconfigurations selectively;

FIG. 17 is a diagram exemplifying a UE operation of determining asubframe for uplink transmission by applying the first and second TDDconfigurations selectively;

FIG. 18 is a flowchart illustrating a UE operation of determining theoperation to perform at the n^(th) subframe by applying the first andsecond TDD configurations selectively;

FIG. 19 is a flowchart illustrating a UE operation of determining asubframe for receiving PHICH by applying the first and second TDDconfigurations selectively;

FIG. 20 is a flowchart illustrating another UE operation of determininga subframe for receiving PHICH by applying the first and second TDDconfigurations selectively;

FIG. 21 is a diagram exemplifying the operation of determining asubframe for receiving PHICH by applying the first and second TDDconfigurations selectively;

FIG. 22 is a flowchart illustrating a UE operation of selecting asubframe for uplink transmission at the UE which has not acquired thesecond TDD configuration temporarily; and

FIG. 23 is a flowchart illustrating a UE operation of selecting asubframe for receiving PHICH at the UE which has not acquired the secondTDD configuration temporarily.

MODE FOR THE INVENTION

Exemplary embodiments of the present invention are described withreference to the accompanying drawings in detail.

Detailed description of well-known functions and structures incorporatedherein may be omitted to avoid obscuring the subject matter of thepresent invention. This aims to omit unnecessary description so as tomake the subject matter of the present invention clear.

For the same reason, some of elements are exaggerated, omitted orsimplified in the drawings and the elements may have sizes and/or shapesdifferent from those shown in drawings, in practice. The same referencenumbers are used throughout the drawings to refer to the same or likeparts.

An embodiment of the present invention relates to a method and apparatusfor providing a user equipment with TDD configuration information anddetermining uplink transmission timing in a mobile communication systemsupporting TDD.

The first and second embodiments are directed to methods of transmittingthe TDD configuration changing at a short cycle to a user equipmentefficiently, and the third embodiment is directed to a method ofdetermining an uplink transmission timing in such situation.

In order to change the ratio between uplink and downlink resourceallocation amounts at a short cycle, it is necessary to change the TDDconfiguration information promptly. For this purpose, it is necessary totransmit the TDD configuration information to the user equipmentquickly. The present invention proposes a method for transmitting thefrequently changing TDD configuration information to the user equipmenteffectively. Prior to the explanation of the present invention, adescription is made of the LTE system, TDD configuration information,and TDD frame structure to which the present invention is applied.

FIG. 1 is a diagram illustrating the architecture of an LTE system towhich the present invention is applied.

As shown FIG. 1, the radio access network of the LTE system includesevolved Node Bs (eNBs) 105, 110, 115, and 120, a Mobility ManagementEntity (MME) 125, and a Serving-Gateway (S-GW) 130. The User Equipment(hereinafter, referred to as UE) 135 connects to an external network viathe eNBs 105, 110, 115, and 120 and the S-GW 130.

In FIG. 1, the eNBs 105, 110, 115, and 120 correspond to the legacy nodeBs of the UMTS system. The eNBs 105, 110, 115, and 120 allow the UE 135to establish a radio channel and are responsible for functions morecomplicated as compared to the legacy node B. In the LTE system, all theuser traffic services including real time services such as Voice overInternet Protocol (VoIP) are provided through a shared channel and thusthere is a need of a device to schedule data based on the stateinformation (such as buffer status, power headroom status, and channelcondition of the UE), the eNBs 105, 110, 115, and 120 being responsiblefor such functions. Typically, one eNB controls a plurality of cells. Inorder to secure the data rate of up to 100 Mbps, the LTE system adoptsOrthogonal Frequency Division Multiplexing (OFDM) as a radio accesstechnology. Also, the LTE system adopts Adaptive Modulation and Coding(AMC) to determine the modulation scheme and channel coding rate inadaptation to the channel condition of the UE. The S-GW 130 is an entityto provide data bearers so as to establish and release data bearersunder the control of the MME 125. The MME 125 is responsible formobility management of UEs and various control functions and may beconnected to a plurality of eNBs.

FIG. 2 is a diagram illustrating a protocol stack of the LTE system towhich the present invention is applied.

Referring to FIG. 2, the protocol stack of the LTE system includesPacket Data Convergence Protocol (PDCP) 205 and 240, Radio Link Control(RLC) 210 and 235, Medium Access Control (MAC) 215 and 230, and Physical(PHY) 220 and 225. The PDCP 205 and 240 is responsible for IP headercompression/decompression, and the RLC 210 and 235 is responsible forsegmenting the PDCP Protocol Data Unit (PDU) into segments inappropriate size. The MAC 215 and 230 is responsible for establishingconnection to a plurality of RLC entities so as to multiplex the RLCPDUs into MAC PDUs and demultiplex the MAC PDUs into RLC PDUs. The PHY220 and 225 performs channel coding on the MAC PDU and modulates the MACPDU into OFDM symbols to transmit over radio channel or performsdemodulating and channel-decoding on the received OFDM symbols anddelivers the decoded data to the higher layer. Also, the PHY layer usesHybrid ARQ (HARQ) for additional error correction by transmitting 1 bitinformation indicating for positive or negative acknowledgement from thereceiver to the transmitter. This is referred to as HARQ ACK/NACKinformation. The downlink HARQ ACK/NACK corresponding to the uplinktransmission is carried by Physical Hybrid-ARQ Indicator Channel(PHICH), and the uplink HARQ ACK/NACK corresponding to downlinktransmission is carried by Physical Uplink Control Channel (PUCCH) orPhysical Uplink Shared Channel (PUSCH).

The LTE standard supports two types of duplex modes including FrequencyDivision Duplex (FDD) and Time Division Duplex (TDD). FDD operates ontwo frequency bands for separate uplink and downlink, and TDD operateswith one frequency band for uplink and downlink. Accordingly, thetransmission alternates between uplink and downlink subframes in TDD.The UE has to know of the uplink and downlink subframes accurately, andthe eNB provides the UE with the subframe information in advance. Theinformation on the uplink and downlink subframes is in the form of a TDDconfiguration, and the eNB notifies the UE of one of 7 TDDconfigurations as shown in table 1. According to the TDD configuration,each subframe is categorized into one of uplink subframe, downlinksubframe, and special subframe. In table 1, D represents downlinksubframe for downlink data transmission, and U represents uplinksubframe for uplink data transmission. The special subframe is thesubframe between consecutive downlink and uplink subframes. The reasonfor interposing the special subframe is that the timing of receiving thedownlink subframe completely and the timing of transmitting uplink datavary depending on the location of the UE. For example, the UE locatedfar from the eNB receives data transmitted by the eNB with a time lag.In contrast, in order for the eNB to receive data transmitted by the UEin a predetermined time, the UE has to start transmitting earlier.Meanwhile, there is no need of the special subframe between consecutiveuplink and downlink subframes. Table 1 shows uplink-downlinkconfigurations.

TABLE 1 Downlink- to-Uplink Uplink- Switch- downlink point Subframenumber configuration periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U U DS U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms  DS U U U D D D D D 4 10 ms  D S U U D D D D D D 5 10 ms  D S U D D D D DD D 6 5 ms D S U U U D S U U D

FIG. 14 is a diagram for explaining a TDD frame structure. The radioframe 1400 spans 10 ms and consists of 10 subframes. Each subframe spans1 ms and consists of two slots. In FIG. 14, the subframes 1405 and 1415are downlink subframes, and the subframes 1410 and 1435 are uplinksubframes, i.e. one of TDD configurations 0, 1, 2, and 6 is used.Accordingly, the subframe between two consecutive downlink and uplinksubframes is the special subframe. The special subframe comprises threeregions represented by Downlink Pilot TimeSlot (DwPTS) 1420, GuardPeriod (GP) 1425, and Uplink Pilot TimeSlot (UpPTS) 1430. There is nodata transmission in GP. The optimal DwPTS and UpPTS value may bedetermined depending on the radio environment. Accordingly, the eNB hasto notify the UE of appropriate DwPTS and UpPTS values as exemplified intable 2. The TDD configuration in table 1 and DwPTS and UpPTS values intable 2 are delivered to the UE in IE Tdd-Config ofSystemInformationBlockType1 (SIB1) broadcast by the eNB. Table 2 showsspecial subframe configurations (lengs of DwPTS/GP/UpPTS).

FIG. 14 is a diagram for explaining a TDD frame structure. The radioframe 1400 spans 10 ms and consists of 10 subframes. Each subframe spans1 ms and consists of two slots. In FIG. 14, the subframes 1405 and 1415are downlink subframes, and the subframes 1410 and 1435 are uplinksubframes, i.e. one of TDD configurations 0, 1, 2, and 6 is used.Accordingly, the subframe between two consecutive downlink and uplinksubframes is the special subframe. The special subframe comprises threeregions represented by Downlink Pilot TimeSlot (DwPTS) 1420, GuardPeriod (GP) 1425, and Uplink Pilot TimeSlot (UpPTS) 1430. There is notdata transmission in GP. The optimal DwPTS and UpPTS value may bedetermined depending on the radio environment. Accordingly, the eNB hasto notify the UE of appropriate DwPTS and UpPTS values as exemplified intable 2. The TDD configuration in table 1 and DwPTS and UpPTS values intable 2 are delivered to the UE in IE Tdd-Config ofSystemInformationBlockType1 (SIB1) broadcast by the eNB. Table 2 showsspecial subframe configurations (lengths of DwPTS/GP/UpPTS).

TABLE 2 Normal cyclic prefix in downlink UpPTS Extended cyclic prefix indownlink Normal UpPTS cyclic Extended Normal cyclic Extended Specialsubframe prefix cyclic prefix prefix in cyclic prefix in configurationDwPTS in uplink in uplink DwPTS uplink uplink 0  6592 · T_(s) 2192 ·T_(s) 2560 · T_(s)  7680 · T_(s) 2192 · T_(s) 2560 · T_(s) 1 19760 ·T_(s) 20480 · T_(s) 2 21952 · T_(s) 23040 · T_(s) 3 24144 · T_(s) 25600· T_(s) 4 26336 · T_(s)  7680 · T_(s) 4384 · T_(s) 5120 · T_(s) 5  6592· T_(s) 4384 · T_(s) 5120 · T_(s) 20480 · T_(s) 6 19760 · T_(s) 23040 ·T_(s) 7 21952 · T_(s) — — — 8 24144 · T_(s) — — —

Table 3 shows the frequency bands concept of the LTE standard. An LTEcarrier belongs to a frequency band, and the parameters to be applied toUE transmit power calculation are determined differently depending onthe frequency band. In a carrier aggregation technique, the carriersbelonging to the same or different bands may be aggregated. In order tosupport the carrier aggregation technique, a UE may be implemented witha plurality of Radio Frequency (RF) modules. If the carriers to be usedby the UE belong to the neighboring frequency bands, the same RF modulecan be used and, otherwise if the carriers belong to the bands far fromeach other in frequency, different RF modules are used. This is becausethe performance characteristic of the RF module varies according to thefrequency applied thereto. If the carriers to be used by the UE belongto the bands adjacent to each other in frequency and thus the same RFmodule is used, the same TDD configuration has to be used. This isbecause it is impossible to split the carriers belonging to an RF moduleto apply the different TDD configurations. In contrast, if the carriersto be used by the UE belong to the bands far from each other infrequency and thus a plurality of RF modules have to be used, differentTDD configurations may be applied to the respective carriers.Accordingly, it is necessary for the UE to notify the eNB of the IMTAtechnology supportability per frequency band. Table 3 shows E-UTRAoperating bands.

TABLE 3 Uplink (UL) operating band Downlink (DL) operating band E-UTRABS receive BS transmit Operating UE transmit UE receive Duplex BandF_(UL low)-F_(UL high) F_(DL low)-F_(DL high) Mode 1 1920 MHz 1980 MHz2110 MHz 2170 MHz FDD 2 1850 MHz 1910 MHz 1930 MHz 1990 MHz FDD 3 1710MHz 1785 MHz 1805 MHz 1880 MHz FDD 4 1710 MHz 1755 MHz 2110 MHz 2155 MHzFDD 5  824 MHz  849 MHz  869 MHz  894 MHz FDD 6  830 MHz  840 MHz  875MHz  885 MHz FDD 7 2500 MHz 2570 MHz 2620 MHz 2690 MHz FDD 8  880 MHz 915 MHz  925 MHz  960 MHz FDD 9 1749.9 MHz   1784.9 MHz   1844.9 MHz  1879.9 MHz   FDD 10 1710 MHz 1770 MHz 2110 MHz 2170 MHz FDD 11 1427.9MHz   1447.9 MHz   1475.9 MHz   1495.9 MHz   FDD 12  699 MHz  716 MHz 729 MHz  746 MHz FDD 13  777 MHz  787 MHz  746 MHz  756 MHz FDD 14  788MHz  798 MHz  758 MHz  768 MHz FDD 15 Reserved Reserved FDD 16 ReservedReserved FDD 17  704 MHz  716 MHz  734 MHz  746 MHz FDD 18  815 MHz  830MHz  860 MHz  875 MHz FDD 19  830 MHz  845 MHz  875 MHz  890 MHz FDD 20 832 MHz  862 MHz  791 MHz  821 MHz FDD 21 1447.9 MHz   1462.9 MHz  1495.9 MHz   1510.9 MHz   FDD 22 3410 MHz 3490 MHz 3510 MHz 3590 MHz FDD23 2000 MHz 2020 MHz 2180 MHz 2200 MHz FDD 24 1626.5 MHz   1660.5 MHz  1525 MHz 1559 MHz FDD 25 1850 MHz 1915 MHz 1930 MHz 1995 MHz FDD 26  814MHz  849 MHz  859 MHz  894 MHz FDD . . . 33 1900 MHz 1920 MHz 1900 MHz1920 MHz TDD 34 2010 MHz 2025 MHz 2010 MHz 2025 MHz TDD 35 1850 MHz 1910MHz 1850 MHz 1910 MHz TDD 36 1930 MHz 1990 MHz 1930 MHz 1990 MHz TDD 371910 MHz 1930 MHz 1910 MHz 1930 MHz TDD 38 2570 MHz 2620 MHz 2570 MHz2620 MHz TDD 39 1880 MHz 1920 MHz 1880 MHz 1920 MHz TDD 40 2300 MHz 2400MHz 2300 MHz 2400 MHz TDD 41 2496 MHz 2690 MHz 2496 MHz 2690 MHz TDD 423400 MHz 3600 MHz 3400 MHz 3600 MHz TDD 43 3600 MHz 3800 MHz 3600 MHz3800 MHz TDD NOTE 1: Band 6 is not applicable

Embodiment 1

In embodiment 1, the eNB transmits dynamic TDD configuration informationwith SIB1 as one of common broadcast informations. Prior to theexplanation thereof, a brief description is made of a normal SIBtransmission method.

FIG. 3 is a diagram for explaining a modification period in a normal SIBtransmission method.

Referring to FIG. 3, the normal SIB transmission method adopts theconcept of modification period 310. That is, it is noted that the SI 300is updated through a paging message during the modification periodbefore the SI update. If a systemInfoModification IE exists in thepaging message, this means that the updated SI 304 begins to betransmitted since the next modification period. Even when only one ofseveral SI messages is updated, this is indicated in the paging message.In the exceptional cases of SIB10 and SIB11 carrying ETWS, they areupdated regardless of the boundary of modification case. If the pagingmessage indicates ETWS along with an etws-Indication IE, the UE attemptsreceiving SIG10 and SIB11 immediately. The length of the modificationperiod is indicated by the SIB2 and has a maximum value of 10.24seconds.

FIG. 4 is a signal flow diagram illustrating a normal SIB transmissionmethod.

Referring to FIG. 4, the eNB determines to update the SIB information atstep 400. The eNB sends the UE the paging message including theSysternInfoModification IE at step 405. The paging message indicatesthat newly updated SIB information begins to be transmitted since thenext modification period. The UE receives the paging message andidentifies that the SIB information is updated in the next modificationperiod at step 410. If the next modification period 420 arrives, the UEattempts decoding SIB1 first at step 425. This is because the SIB1 hasthe scheduling information for other SIBs. The UE receives the newlyupdated SIB information at step 430. The UEs applies the modified SIBinformation at step 435.

FIG. 5 is a diagram for explaining a normal SIB scheduling method.

Referring to FIG. 5, the common information broadcast by the eNBincludes the MIB (MasterInformationBlock) 545 and SIB1 to SIB13, andSIB14 is being discussed for supporting new technologies. The MIBincludes most essential information such as System Frame Number (SFN)and frequency bandwidth. The MIB is transmitted at the first subframe ofevery radio frame 535. Since the MIB carries the same information duringthe four consecutive radio frame, its period is 40 ms. The SIB1 550includes cell access and SIB scheduling information. The SIB2 istransmitted in the fifth subframe of every even-numbered radio frame.The rest SIB2˜SIB13 are transmitted in one of a plurality of SI messages555, 560, and 565. The SI message including the plural SIBs istransmitted during the SI window which is a time duration defined bySi-WindowLength 525, and other SI message may be transmittedoverlappingly for the time duration. The Si-WindowLength is notified tothe UE by means of the SIB1 and set to a value which applied to all SImessages commonly. The SIB informations included in one SI message aretransmitted in one subframe sequentially according to the schedulinginformation during the SI window. Among the subframes within the SIwindow, MBSFN subframes, TDD uplink subframes, subframes carrying theSIB1 (the fifth subframes of even-numbered radio frame) are restrictivefor SIB transmission. The SIB2 530 is fixed as the first SIB informationof the first SI message. The first SI message 555 is transmittedrepeatedly at a predetermined period 505. That is, the first SI message555 transmitted in the first SI window 515 is retransmitted after thepredetermined period 505. The second SI message 560 is transmitted inthe second SI window 520 and then retransmitted repeatedly at anotherperiod 510. The transmission periods of the respective SI messages arenotified to the UE in the SIB1.

In order to notify the UE of the dynamic TDD configuration informationwhich varies at an interval of a few or a few hundred ms, SIB1 is mostsuitable among the above-described SIBs. The MIB includes only the mostessential information and has not many surplus bits. Meanwhile, the SIB1is longer than MIB and transmitted at a relatively long interval but itis short in comparison to other SIBs. Since the SIB1 is transmittedrepeatedly at a designated subframe, no scheduling information isneeded. As described above, the other SIB informations can be receivedwith the scheduling information acquired from another SIB. In the caseof using SIB1, the problem occurs in the modification period-based SIBtransmission procedure. Assuming that the SIB1 includes dynamic TDDconfiguration, it is necessary to notify that the ISB is to be updatedthrough paging at the previous modification period of the time oftransmitting the modified SIB1 in order to send the updated dynamic TDDconfiguration to the UE. After the modification period elapses, the eNBtransmits the modified SIB1. This means that the updated dynamic TDDconfiguration cannot be notified to the UE at the right time by takingnotice of the modification period of the dynamic TDD configuration. Thepresent invention proposes an SIB1 transmission method in which the eNBincludes the dynamic TDD configuration information in the SIB1immediately as soon as the dynamic TDD configuration information isupdated and the UE receives and decodes the SIB1 continuously other thanabiding by the legacy modification period.

FIG. 6 is a signal flow diagram illustrating the embodiment 1.

Referring to FIG. 6, the UE establishes an RRC connection with the eNBsupporting TDD at step 600. The UE provides the eNB with the capabilitybits indicating the per-frequency band dynamic TDD configurationcapabilities at step 605. The reason why per-frequency band capabilitybits are required has been described above. The eNB determines whetherto apply the dynamic TDD configuration on the specific carrier belongingto a specific band to the UE at step 610. The eNB sends the UE anRRCConnectionReconfiguration message to trigger the dynamic TDD. Uponreceipt of this message, the UE receives and decodes the SIB1information transmitted periodically at step 620. The UE acquires thedynamic TDD configuration information from the SIB1 at step 630. The UEperforms the dynamic TDD using the dynamic TDD configuration receivedlastly at step 635 until any updated dynamic TDD configurationinformation. The UE receives the updated dynamic TDD configurationinformation at step 640. The UE repeats the above operation until thedynamic TDD operation ends.

FIG. 7 is a flowchart illustrating the UE operation in the embodiment 1.

Referring to FIG. 7, the UE generates a UE capability informationmessage including capability indicators indicating per-frequency banddynamic TDD operation supportabilities at step 700. The UE sends the eNBthe UE capability information message at step 705. The UE receives anRRCConnectionReconfiguration message from the eNB at step 710. The UEdetermines whether to configure dynamic TDD operation based on themessage at step 715. If it is determined to configure the dynamic TDDoperation, the UE acquires the dynamic TDD configuration informationfrom the SIB1 which is broadcast periodically at step 720. The UEperforms the dynamic TDD operation based on the last dynamic TDDconfiguration information at step 725. If it is determined not toconfigure the dynamic TDD operation, the UE performs the legacy TDDoperation at step 730.

FIG. 8 is a flowchart illustrating the eNB operation in the embodiment1.

Referring to FIG. 8, the eNB receives a UE capability informationmessage including capability indicators indicating per-frequency banddynamic TDD operation supportabilities at step 800.

The eNB determines whether to configure dynamic TDD operation based onthe message at step 805. If it is determined to configure the dynamicTDD operation, the eNB configures the dynamic TDD operation using theRRCConnectionReconfiguration message at step 810. The eNB transmits theRRCConnectionReconfiguration message to the UE at step 820. The eNBbroadcasts the SIB1 including the last dynamic TDD configuration at step825.

Embodiment 2

In embodiment 2, the dynamic TDD configuration information istransmitted in the paging message. Prior to the explanation thereof, adescription is made of the normal paging transmission method.

The paging message is transmitted in a subframe of a radio framepredetermined per UE. Since both the eNB and UE know the transmissiontiming, the UE attempts receiving the paging message only at thetransmission timings. The radio frame in which the paging message istransmitted is referred to as Paging Frame (PF), and the subframecarrying the paging message in the PF is referred to as Paging Occasion(PO). The PF and PO are derived by the following two equations.

SFN mod T=(T div N)*(UE_ID mod N)   (1)

i_s=floor(UE_ID/N)modN _(s)   (2)

Here, T denotes the DRX cycle. nB is set to a value of {4T, 2T, T, T/2,T/4, T/8, T/16, T/32}. N is a value of min(T,nB). Ns is a value ofmax(1,nB/T). The UE_ID is defined as IMSI mode 1024, and IMSI is the UEID. i_s is derived using the following table. Table 4 shows the TDDconfigurations (all UL/DL configurations).

TABLE 4 PO PO PO PO when Ns when i_s = 0 when i_s = 1 when i_s = 2 i_s =3 1 0 N/A N/A N/A 2 0 5 N/A N/A 4 0 1 5 6

In this embodiment, three bits for indicating the TDD configuration isadded to the paging message. Also, in order to reduce the signalingoverhead of PDCCH, the paging message for dynamic TDD configuration maybe transmitted with the fixed PF and PO. The paging message for thedynamic TDD configuration is not required to be received by all of theUEs but the UEs having the dynamic TDD capability in the connected mode.The eNB sends the UE having the dynamic TDD configuration thePagingCycle-dynamic-TDD and i_s-dynamic-TDD information using adedicated RRC message. The PagingCycle-dynamic-TDD denotes the period ofthe radio frame carrying the paging message including the dynamic TDDconfiguration information (PF period). The i_s-dynamic-TDD denotes thePO. The i_s-dynamic-TDD may be defined as shown in table 4.

FIG. 15 is a diagram for explaining the pagingCycle-dynamic-TDD andi_s-dynamic-TDD information.

Referring to FIG. 15, the PagingCycle-dynamic-TDD 1500 is thetransmission period of the paging message including the dynamic TDDconfiguration. The PF 1505 denotes the radio frame in which the pagingmessage including the dynamic TDD configuration information istransmitted. The PO 1510 is the subframe carrying the paging messageindicated by the i_s-dynamic-TDD. The dynamic TDD configurationinformation received through the padding message is applied until thenext paging message is received as denoted by reference number 1515.

FIG. 9 is a signal flow diagram of embodiment 2.

Referring to FIG. 9, the UE establishes an RRC connection with the eNBsupporting TDD at step 900. The UE sends the eNB the capability bitsindicating per-frequency band dynamic TDD configuration supportabilitiesat step 905. The necessity of the per-frequency band capability bits hasbeen described in detail above. The eNB determines whether to configurethe dynamic TDD on a specific carrier belonging to the specific band tothe UE at step 910. The eNB sends the UE theRRCConnectionReconfiguration message including thePagingCycle-dynamic-TDD and i_s-dynamic-TDD information at step 915.Upon receipt of this message, the UE receives and decodes the paginginformation transmitted periodically at step 920. The UE acquires thedynamic TDD configuration information from the paging message at step930. The UE performs the dynamic TDD by applying the last dynamic TDDconfiguration until any updated dynamic TDD configuration information isreceived at step 935. The UE receives the updated dynamic TDDconfiguration information at step 940. The UE repeats the aboveoperation until the dynamic TDD operation ends.

FIG. 10 is a flowchart illustrating the UE operation in the embodiment2.

Referring to FIG. 10, the UE generates a UE capability informationmessage including capability indicators indicating per-frequency banddynamic TDD operation supportabilities at step 1000. The UE sends theeNB the UE capability information message at step 1005. The UE receivesthe RRCConnectionReconfiguration message from the eNB at step 1010. TheUE determines whether the message includes the dynamic TDD operationconfiguration and PagingCycle-dynamic-TDD and i_s-dynamic-TDDinformation at step 1015. If the dynamic TDD operation is configured,the UE acquires dynamic TDD configuration information from the pagingmessage transmitted periodically at step 1020. The UE performs thedynamic TDD operation by applying the last dynamic TDD configurationinformation at step 1025. If the dynamic TDD operation is notconfigured, the UE performs the legacy TDD operation at step 1030.

FIG. 11 is a flowchart illustrating the eNB operation in the embodiment2.

Referring to FIG. 11, the eNB receives the UE capability informationmessage including the capability indicators indicating per-frequencyband dynamic TDD operation supportabilities at step 1100.

The eNB determines whether to configure the dynamic TDD operation basedon the message at step 1105. If it is determined to configure thedynamic TDD operation, the eNB sends the RRCConnectionReconfigurationmessage including the PagingCycle-dynamic-TDD and i_s-dynamic-TDDinformation at step 1110. The eNB sends the UE theRRCConnectionReconfiguration message at step 1120. The eNB transmits thepaging message including the last dynamic TDD configuration at step1125.

Embodiment 3

The UE is allocated transmission resource for PUSCH transmission in twoways as follows.

1. Receiving uplink grant indicating initial transmission orretransmission through downlink control channel (PDCCH)

2. Receiving uplink grant containing valid Random Access Response (RAR)in random access procedure

When the UE receives the uplink grant at the n^(th) subframe, itperforms uplink transmission after a predetermined time, e.g. at the(n+k)^(th) subframe. Here, k relates to the time required for generatingMAC PDU and preprocessing at the physical layer for uplink transmissionand set to the same value for the UE and eNB.

The embodiment 3 of the present invention proposes a method andapparatus of selecting an uplink subframe for uplink transmissiondifferently depending on whether the uplink grant is received through adownlink control channel or RAR. Particularly in the case that thedynamic TDD operation is configured to the UE, k is determined byapplying a second TDD configuration for the case of receiving the uplinkgrant through PDCCH and by applying a first TDD configuration for thecase of receiving the uplink grant through RAR.

FIG. 16 shows the UE operation of the present invention.

For reference, the TDD configuration information is an integer between 0and 6 which indicates the configuration of downlink, uplink, and specialsubframes in a radio frame. In the present invention, two types of TDDconfiguration informations are used. The first TDD configurationinformation is the information that can be understood by the terminalsincluding the terminal which does not supporting the dynamic TDDoperation and transmitted through the system information which all ofthe terminal can receive in the corresponding cell. The systeminformation may be the System Information Block 1. The SIB1 istransmitted repeatedly at a predetermined interval and includesessential information for used in determining whether to camp on thecorresponding cell such as network provider information of thecorresponding cell as well as the first TDD configuration information.The first TDD configuration information may be contained in a fieldwhich all of the UEs including initial release UEs can understand, i.e.legacy field. The second TDD configuration information is understood byonly the UEs supporting the dynamic TDD operation and transmitted to theUEs in various ways. The second TDD configuration information istransmitted repeatedly at a predetermined interval and may be changeddynamically. The eNB determines the most suitable TDD configuration at apredetermined timing in consideration of the load condition of thecurrent cell and ratio between downlink and uplink traffics and thensends the UEs configured for the dynamic TDD operations the second TDDconfiguration information in a predetermined method.

Referring to FIG. 16, the UE acquires the first TDD configurationinformation at step 1605. As described above, the UE receivespredetermined system information and checks the first TDD configurationinformation contained in the legacy field of the system information. Thefirst TDD configuration information has a property of not changingfrequently and, if it is changed, this triggers a system informationmodification procedure. The dynamic TDD operation is configured to theUE at step 1610. If the dynamic TDD operation is configured, this meansthat the UE receives the control message including the controlinformation instructing to start the dynamic TDD operation. The dynamicTDD operation is the operation of changing the TDD configuration of theUE dynamically according to the load state of the cell. The dynamic TDDoperation is categorized into two types as follows.

Dynamic TDD operation 1: The TDD configuration may be modified at apredetermined interval, and the eNB notifies the UE of the TDDconfiguration to be applied at the current time or in the near futureusing a predetermined method, e.g. predetermined control information,periodically. The TDD configuration information is an integer between 0and 6 like the legacy TDD configuration information and indicates theconfiguration of the uplink, downlink, and special subframes.

Dynamic TDD operation 2: The 10 subframes forming a radio frame aresorted into fixed subframes and flexible subframes. A fixed subframe isfixed as a downlink subframe, uplink subframe, or special subframe; anda flexible subframe may be used as a downlink subframe or an uplinksubframe. For example, the subframes may be defined as shown in table 5.

TABLE 5 fixed downlink subframe subframes #0, #5 fixed uplink subframesubframes #1, #6 fixed special subframe subframes #2, #7 flexiblesubframe subframes #3, #4, #8, #9

An embodiment of the present invention is applicable to both the dynamicTDD operations 1 and 2. However, in view of the detailed operation ofthe UE, part of the operation is applicable to one of the two dynamicTDD operations.

The UE acquires the second TDD configuration information at step 1615.The second TDD configuration information is sent to the UE through apredetermined control message. The predetermined control message may bethe system information, an RRC control message, a MAC control message,or a message transmitted on PDCCH. Step 1615 is applied only to thedynamic TDD operation 1.

The UE receives a valid uplink grant at the n^(th) subframe at step1620.

The UE determines whether the valid uplink grant is received through theRAR or PDCCH at step 1625. If the valid uplink grant is received throughthe RAR, the procedure goes to step 1630 and, otherwise if the validuplink grant is received through the PDCCH, the procedure goes to step1645. If the valid uplink grant is received through the RAR, this hasthe meaning as follows.

The RAR is a response message transmitted by the eNB in reply to thepreamble transmitted by the UE and includes a header and a payload, theheader containing Random Access Preamble ID (RAPID) and the payloadcontaining various informations as well as uplink grant. The UE monitorsto receive an RAR during a predetermined period after transmitting therandom access preamble and, if the RAR includes the same RAPID as thepreamble it has transmitted, determines that the RAR and the uplinkgrant included in the RAR are valid.

If the valid uplink grant is received through PDCCH, this means that theuplink grant masked with the UE identifier (C-RNTI) is received throughthe PDCCH.

The UE determines whether the preamble which has triggered the RARtransmission is the dedicated preamble or random preamble at step 1630.The random access procedure includes transmitting, at the UE, apreamble, transmitting, at the eNB, an RAR, and performing, at the UE,uplink transmission according to the uplink grant of the RAR (this isexpressed as transmitting a message 3). In the random access procedure,the UE selects the preamble by itself, or the eNB instructs to use aspecific preamble. The former case is of being called use of a randompreamble, and the latter case is of being called use of a dedicatedpreamble. In the case of using the random preamble, the eNB does notknow which UE is performing the random access procedure until themessage 3 is received successfully. In the case of using the dedicatedpreamble, however, the eNB can identify the UE upon receipt of thepreamble. For example, the eNB recognizes whether the UE supports thedynamic TDD upon receipt of the message 3 in the case of using therandom preamble and upon receipt of the preamble in the case of usingthe dedicated preamble. If the UE receives the RAR in response to therandom preamble, this means that the eNB has transmitted the uplinkgrant to the UE in the state of not knowing whether the UE had beenconfigured for the dynamic TDD operation and thus the procedure goes tostep 1635. If the UE receives the RAR in response to the dedicatedpreamble, this means that the eNB has transmitted the uplink grant tothe UE in the state of knowing that the UE supports the dynamic TDDoperation and thus the procedure goes to step 1640.

The UE determines the subframe for uplink transmission by applying theTDD configuration indicated in the first TDD configuration informationat step 1635. If the procedure goes to step 1635, this means that the UEconfigured for the dynamic TDD transmits the random access preamble andreceives the RAR in response thereto. Although the dynamic TDD operationis applied in a certain cell, since there may be the cells which do notsupport the dynamic TDD operation within the cell, in the case where theeNB cannot identify the UE until a predetermined time after performingan operation such as the random access operation, even though the UE isconfigured for the dynamic TDD operation, it is preferred to determinethe uplink subframe by applying the same rule as the other UEs which arenot configured for the dynamic TDD operation other than the uplinksubframe determined by the dynamic TDD operation. Accordingly, at step1635, the UE determines the subframe for uplink transmission by applyingthe TDD configuration indicated in the first TDD configurationinformation. This means the operation described in detail as follows.The UE performs uplink transmission at the (n+k1)^(th) subframe for theuplink grant received at the n^(th) subframe. Here, k1 is an integerequal to or greater than 6 corresponding to the first uplink subframesince the (n+6)^(th) subframe. Whether a subframe is an uplink subframemay be determined differently depending on the TDD configuration, andthe UE determines which is the first uplink subframe since the(n+6)^(th) subframe by applying the first TDD configuration and performsuplink transmission based on the determination result at step 1635. Atthis time, although the subframe which is determined as the first uplinksubframe since the (n+6)^(th) subframe according to the first TDDconfiguration information is a downlink subframe or a flexible subframeaccording to the second TDD configuration information, the UE operatesunder the assumption that the subframe is the uplink subframe. The RARuplink grant may include uplink transmission resource information,modulation scheme and coding rate for uplink transmission, size of datato be transmitted, and 1-bit information indicating whether uplinktransmission is delayed (hereinafter referred to as uplink transmissiondelay information). If the uplink transmission delay information is setto 0, the UE performs uplink transmission at the uplink subframecorresponding to k1. If the uplink transmission delay information is setto 1, the UE performs uplink transmission at the first uplink subframesince the uplink subframe corresponding to k1. At this time, the UEdetermines the first uplink subframe since the subframe corresponding tok1 based on the TDD configuration indicated in the first TDDconfiguration information. The uplink transmission delay is a kind ofload balancing.

The UE determines the subframe for uplink transmission by applying thesecond TDD configuration at step 1640. If the procedure goes to step1640, the UE configured for the dynamic TDD operation transmits thededicated preamble and receives a response message in reply thereto.This means that the eNB transmits the uplink grant in the state ofknowing that the UE had been configured for the dynamic TDD and thus theUE applies the second TDD configuration information. In more detail, theUE performs uplink transmission at the (n+k1)^(th) subframe, and k1 isan integer equal to or greater than 6 and corresponds to the firstuplink subframe based on the TDD configuration indicated in the secondTDD configuration information. If the uplink transmission delayinformation of the RAR is set to 0, the UE selects k1 based on thesecond TDD configuration and performs uplink transmission at the(n+k1)^(th) subframe. If the uplink transmission delay information ofthe RAR is set to 1, the UE performs uplink transmission at the firstuplink subframe since the subframe corresponding to the k1 selectedbased on the second TDD configuration. At this time, the UE determinesthe first uplink subframe since the subframe corresponding to k1 basedon the second TDD configuration.

If the procedure goes to step 1645, this means that the eNB which knowsthat the UE is configured for the dynamic TDD operation transmits thedownlink grant to the corresponding UE. The UE determines the subframefor uplink transmission based on the second TDD configuration. Thetiming relationship between the uplink grant received through PDCCH andthe uplink transmission corresponding thereto is defined per TDDconfiguration in table 8-2 (table 6) of standard 36.213

TABLE 6 TDD UL/DL subframe number n Configuration 0 1 2 3 4 5 6 7 8 9 04 6 4 6 1 6 4 6 4 2 4 4 3 4 4 4 4 4 4 5 4 6 7 7 7 7 5

For example, when the UE receives the uplink grant at the 0^(th)subframe, k is 4 for the TDD configuration 0 and 7 for the TDDconfiguration 6.

The above operation is described with the example of FIG. 17.

Referring to FIGS. 16 and 17, the first TDD configuration 1705 is theTDD configuration 0, and the second TDD configuration 1710 is the TDDconfiguration 3. The UE receives the uplink grant at the 0^(th) subframe1715. If the uplink grant is received through the RAR and a randompreamble has been transmitted by the UE, the UE determines k1 based onthe first TDD configuration. That is, among the subframes after 6^(th)subframe, when applying the TDD configuration 0, the first uplinksubframe corresponds to k1, i.e. the 7^(th) subframe in the aboveexample. If the uplink transmission delay information is set to 0, theUE performs uplink transmission at the 7^(th) subframe 1720. If theuplink transmission delay information is set to 1, the UE determines thesubframe corresponding to k1 by applying the first TDD configuration andthe first uplink subframe 1725 since then by applying the first TDDconfiguration. At the subframe, uplink transmission is performed.

If the uplink grant is received through the RAR and the UE hastransmitted a dedicated preamble, the UE determines k1 by applying thesecond TDD configuration. That is, among the subframes after at leastthe 6^(th) subframe, when applying the TDD configuration 3, the firstuplink subframe is k1, i.e. the 12^(th) subframe in the above example.If the uplink transmission delay is set to 0, the UE performs uplinktransmission at the 2^(nd) subframe 1730. If the uplink transmissiondelay is set to 1, the UE determines the subframe indicated by k1 andthen checks the first uplink subframe 1735 since then based on thesecond TDD configuration. Then the uplink transmission is performed atthat subframe.

If the uplink grant is received through PDCCH, the UE determines k byapplying the second TDD configuration. Referring to table 8-2, the TDDconfiguration 3 is applied and the uplink grant is received at the0^(th) subframe, k is 4. Accordingly, the UE performs uplinktransmission at the 4^(th) subframe 1740.

The above embodiment is directed to an example of using the dynamic TDDoperation 1. A description is made of the difference in the case ofusing the dynamic TDD operation 2 hereinafter.

Steps 1605 and 1610 are identically applied to the case of using thedynamic TDD operation 2.

In the case of applying the dynamic TDD operation 2, step 1615 is notneeded.

Steps 1620 to 1635 are also identically applied to the case of using thedynamic TDD operation 2.

At step 1640, the UE performs uplink transmission at the first subframeamong the uplink subframes and flexible subframes since the 6^(th)subframe after the subframe in which the uplink grant is received. Thatis, k1 is an integer which is greater than 6 and corresponds to thesubframe appearing first between the first uplink subframe and the firstflexible subframe. In the example of FIG. 17, the UE performs uplinktransmission at the 7^(th) subframe 1720 (if the uplink transmissiondelay information is set to 0) or the 8^(th) subframe 1725 (if theuplink transmission delay information is set to 1).

At step 1645, the UE performs uplink transmission at the first subframeamong the uplink subframes and flexible subframes since the 4^(th)subframe after the subframe in which the uplink grant is received. Thatis, k is an integer which is greater than 4 and corresponds to thesubframe appearing first between the first uplink subframe and the firstflexible subframe. In the example of FIG. 17, the UE performs uplinktransmission at the 4^(th) subframe 1740.

The UE determines the operation to perform at the n^(th) subframe beforethe n^(th) subframe begins. Examples of the operation include monitoringPDCCH at the corresponding subframe, transmitting uplink feedback,receiving downlink feedback, and transmitting PUSCH. The UE monitors thePDCCH at the downlink subframes to determine whether there is anyscheduling or data present for it. If the UE is configured for thedynamic TDD operation, it determines the operation to perform byapplying the first and second TDD configurations selectively. The UEwhich is not configured for the dynamic TDD operation always determinesthe operation to perform by applying the first TDD configuration.

FIG. 18 is a flowchart illustrating a UE operation of determining theoperation to perform at the n^(th) subframe by applying the first andsecond TDD configurations selectively.

Referring to FIG. 18, the UE starts a procedure of determining whetherto perform the downlink subframe-related operation or uplinksubframe-related operation in a certain subframe at step 1805.

The UE determines whether the dynamic TDD operation is configured atstep 1810. If the dynamic TDD operation is not configured, the proceduregoes to step 1815 and, otherwise, step 1820.

The UE operates as follows at step 1815.

The UE determines whether a scheduling message masked with a C-RNTI isreceived through PDCCH in the corresponding subframe by applying thefirst TDD configuration. If the corresponding subframe is a downlinksubframe or a special subframe when the first TDD configuration isapplied, the UE monitors the PDCCH in the subframe to receive thescheduling message masked with the C-RNTI.

The UE determines whether to receive HARQ feedback at the correspondingsubframe by applying the first TDD configuration. The timingrelationship between the PUSCH transmission and HARQ feedback isspecified per TDD configuration in standard 36.213. If the correspondingsubframe is a downlink subframe in the first TDD configuration, the UEdetermines whether the PUSCH has been transmitted at a previous uplinksubframe to receive the HARQ feedback in the subframe.

The UE determines whether to transmit PUSCH at the correspondingsubframe by applying the first TDD configuration. If the correspondingsubframe is an uplink subframe and the uplink grant is received throughPDCCH before k subframes, the UE transmits PUSCH at the correspondingsubframe. Here, k is determined based on the first TDD configuration.

The UE determines whether to transmit an uplink HARQ feedback at thecorresponding subframe by applying the first TDD configuration. If thecorresponding subframe is an uplink subframe and PDSCH is receivedbefore a predetermined period specified per TDD configuration based onthe first TDD configuration, the UE transmits the uplink HARQ feedback.

The UE determines whether an RAR masked with an RA-RNTI is receivedthrough PDCCH at the corresponding subframe by applying the first TDDconfiguration. If the UE has transmitted a preamble at the x^(th)subframe and if the corresponding subframe is a subframe between the(x+m)^(th) and (x+m+k)^(th) subframes and if the corresponding subframeis a downlink subframe or a special subframe based on the first TDDconfiguration, the UE monitors the PDCCH in the corresponding subframefor receiving the RAR masked with the RA-RNTI. Here, m and k areparameters for the random access response window specifying the durationfor attempting to receive the RAR after transmitting the preamble. m isa fixed value, and k is a parameter the length of which is notified bythe system information. If no valid RAR is received before the expiry ofthe RAR window, the UE enters the preamble retransmission procedure.

The UE determines whether to receive PUSCH in response to the RAR uplinkgrant at the corresponding subframe by applying the first TDDconfiguration. If the corresponding subframe is an uplink subframe andthe uplink grant is received through the RAR before k1 subframes, the UEtransmits PUSCH at the corresponding subframe. Here, k1 is determinedbased on the first TDD configuration.

At step 1820, the UE operates as follows. In summary, the UE applies thefirst TDD configuration for transmitting a message 3 and receiving anRAR and the second TDD configuration for other purposes.

The UE determines whether to monitor the PDCCH to receive the schedulingmessage masked with a C-RNTI at the corresponding subframe by applyingthe second TDD configuration. If the corresponding subframe is an uplinksubframe or a special subframe in the case of applying the second TDDconfiguration, the UE monitors PDCCH to receive the scheduling messagemasked with a C-RNTI in the subframe.

The UE determines whether to receive HARQ feedback at the correspondingsubframe by applying the second TDD configuration. The timingrelationship between the PUSCH transmission and the HARQ feedbackreception is specified per TDD configuration in the standard 36.213. Ifthe corresponding subframe is a downlink subframe based on the secondTDD configuration, the UE determines whether to receive the HARQfeedback in the corresponding subframe based on the second TDDconfiguration.

The UE determines whether to transmit PUSCH at the correspondingsubframe by applying the second TDD configuration. If the correspondingsubframe is an uplink subframe and if an uplink grant is receivedthrough PDCCH before k subframes, the UE transmits PUSCH at thecorresponding subframe. Here, k is determined based on the second TDDconfiguration.

The UE determines whether to transmit an uplink HARQ feedback at thecorresponding subframe by applying the second TDD configuration. If thecorresponding subframe is an uplink subframe and if PDSCH is receivedbefore a time period determined per TDD configuration, the UE transmitsthe uplink feedback.

The UE determines whether to monitor PDCCH to receive the RAR maskedwith a RA-RNTI at the corresponding subframe by applying the first TDDconfiguration. If the UE has transmitted a preamble at the x^(th)subframe and if the corresponding subframe is a subframe between the(x+n+m)^(th) and (x+m+k)^(th) subframes and if the correspondingsubframe is a downlink subframe or a special subframe based on the firstTDD configuration, the UE monitors PDCCH to receive the RAR masked withthe RA-RNTI in the corresponding subframe. Here, m and k are parametersfor the random access response window specifying the duration forattempting to receive the RAR after transmitting the preamble. m is afixed value, and k is a parameter the length of which is notified by thesystem information. If no valid RAR is received before the expiry of theRAR window, the UE enters the preamble retransmission procedure.

The UE determines whether to transmit PUSCH in response to an RAR uplinkgrant in the corresponding subframe by applying the first TDDconfiguration. If the corresponding subframe is an uplink subframe andif the uplink grant is received through the RAR before k1 subframes, theUE transmits PUSCH at the corresponding subframe. Here, k1 is determinedbased on the first TDD configuration.

Another UE operation is described hereinafter.

The random access procedure includes transmitting a preamble at theterminal, transmitting a random access response at the eNB, andtransmitting uplink data at the UE. At this time, the UE transmitsuplink data and receives an HARQ feedback corresponding thereto. If theUE is configured for the dynamic TDD operation, the UE determines thetiming of receiving the HARQ feedback by applying the first and secondTDD configurations selectively.

FIG. 19 shows a related UE operation.

Referring to FIG. 19, the UE acquires the first TDD configurationinformation at step 1905. As described above, the UE receivespredetermined system information and checks the first TDD configurationinformation contained in the legacy field of the system information. Thefirst TDD configuration information has a property of not changingfrequently and, if it changes, a system information modificationprocedure is applied. The dynamic TDD operation is configured to the UEat step 1910. If the dynamic TDD operation is configured, this meansthat the UE receives a control message including the control informationindicating that the dynamic TDD operation starts. The dynamic TDDoperation means the operation of modifying the TDD configuration of theUE dynamically in adaptation to the load state of the UE.

The UE acquires the second TDD configuration information at step 1915.The second TDD configuration information is transmitted to the UEthrough a predetermined control message. The predetermined controlmessage may be the system information, an RRC control message, a MACcontrol message, or a message transmitted on PDCCH. Step 1915 is appliedonly to the dynamic TDD operation 1.

The UE receives a downlink HARQ feedback at a subframe i at step 1920.The downlink HARQ feedback is transmitted/received through a PhysicalHARQ Indicator Channel (PHICH) and thus, if the downlink HARQ feedbackis received, this has the same meaning as receiving the PHICH. In orderfor the UE to determine the uplink subframe in which the PUSCHcorresponding to the HARQ ACK/NACK has been transmitted, the proceduregoes to step 1925.

The UE determines whether the uplink grant triggered the PUSCHtransmission corresponding to the received PHICH has been transmittedthrough RAR or PDCCH at step 1925. If the uplink grant has beentransmitted through RAR, the procedure goes to step 1930 and, otherwise,step 1940. At step 1930, the UE determines whether the preambletriggered the RAR transmission (or the preamble corresponding to RAPIDcontained in the RAR) is a dedicated preamble or a random preamble. Ifthe UE receives the RAR in response to the random preamble, this meansthat the eNB has transmitted the uplink grant to the UE in the state ofnot knowing whether the UE had been configured for the dynamic TDDoperation and thus the procedure goes to step 1935. If the RAR isreceived in response to the dedicated preamble, this means that the eNBhas transmitted the uplink grant to the UE in the state of knowing thatthe UE had been configured for the dynamic TDD operation and thus theprocedure goes to step 1940.

The UE determines the uplink subframe in which the PUSCH correspondingto the PHICH has been transmitted by applying the TDD configurationindicated in the first TDD configuration information at step 1935. Forexample, the PHICH corresponds to the PUSCH transmitted at the(i+k)^(th) subframe, and k is determined based on the TDD configurationindicated in the first TDD configuration information. The relationshipbetween TDD and k is specified in table 8.3-1 of the standard 36.213 asshown in table 7. For example, if the UE receives the PHICH at the0^(th) subframe and if the TDD configuration 0 is applied at thecorresponding timing, k is 7 and the PHICH is the HARQ feedbackcorresponding to the PUSCH transmitted at the (i+7)^(th) subframe.

Table 7 shows table 8.3-1 of the standard 36.213. The table shows thevalue k in the respective TDD configurations 0 to 6.

TABLE 7 TDD subframe number i UL/DL configuration 0 1 2 3 4 5 6 7 8 9 07 4 7 4 1 4 6 4 6 2 6 6 3 6 6 6 4 6 6 5 6 6 6 4 7 4 6

The UE determines whether the uplink subframe in which the PUSCHcorresponding to the PHICH has been transmitted by applying the TDDconfiguration indicated in the second TDD configuration information atstep 1940. For example, the PHICH corresponds to the PUSCH transmittedat the (i+k)^(th) subframe, and k is determined based on the TDDconfiguration indicated in the second TDD configuration information. Therelationship between the TDD configuration and k is specified in table8.3-1 of the standard 36.213.

FIG. 20 shows another operation of the UE in association of the aboveoperation.

Referring to FIGS. 19 and 20, the operations depicted in FIGS. 20 and 19are led to the same result and thus provide the same effect.

Steps 2005 to 2015 are identical with steps 1905 to 1915.

The UE performs PUSCH transmission at the n^(th) subframe at step 2005.The UE determines the subframe for receiving feedback corresponding tothe PUSCH at step 2025.

At step 2025, the UE determines whether the uplink grant triggering thePUSCH transmission has been transmitted through RAR or PDCCH. If it hasbeen received through RAR, the procedure goes to step 2030 and,otherwise if it has been received through PDCCH, step 2040.

At step 2030, the UE determines whether the preamble corresponding tothe RAR is a dedicated preamble or a random preamble. If the RAR isreceived in response to a random preamble, this means that the eNB hastransmitted the uplink grant to the UE in the state of not knowingwhether the UE had been configured for the dynamic TDD operation andthus the procedure goes to step 2035. If the RAR is received in responseto a dedicated preamble, this means that the eNB has transmitted theuplink grant to the UE in the state of knowing that the UE had beenconfigured for the dynamic TDD operation and thus the procedure goes tostep 2040.

At step 2035, the UE determines the subframe for receiving PHICH byapplying the first TDD configuration. For example, the UE receives PHICHat the (n+k)^(th) subframe. Here, k is determined according to the TDDconfiguration indicated in the first TDD configuration information. Therelationship between TDD configuration and k may be determined byreferencing table 8.3-1 of the standard 36.213. For example, if the UEhas transmitted the PUSCH at the 2^(nd) subframe and the TDDconfiguration is the TDD configuration 1, the PHICH is received at the6^(th) subframe.

At step 2040, the UE determines the subframe for receiving PHICH byapplying the second TDD configuration. For example, the UE receives thePHICH at the (n+k)^(th) subframe.

A description is made of an example of the above operation withreference to FIG. 21.

In FIG. 21, the first TDD configuration is the configuration 0 asdenoted by reference number 2105 and the second TDD configuration is theconfiguration 3 as denoted by reference number 2110. The UE transmitsPUSCH at the 3^(rd) subframe as denoted by reference number 2115. If theuplink grant associated with the PUSCH transmission has been receivedthrough RAR and if the UE had transmitted a random preamble, the UEdetermines k by applying the first TDD configuration. Referring to FIG.table 8.3-1, since k of the 0^(th) subframe is 7 in the TDDconfiguration 3 and the distance between the 0^(th) subframe and the3^(rd) subframe is 7 so as to match each other in the TDD configuration0 when the PUSCH has been transmitted at the 3^(rd) subframe, the UEsets k to 7 and receives the PHICH at the 0^(th) subframe 2120. If theuplink grant has been received through RAR and if the UE has used thededicated preamble or if the uplink grant has been received throughPDCCH, the UE determines k based on the second TDD configuration.Referring to table 8.3-1, since the PUSCH has been transmitted at the3^(rd) subframe and k of the 9^(th) subframe is 6 and the distancebetween the 9^(th) subframe and the 3^(rd) subframe is 6 so as to matcheach other, the UE sets k to 6 and receives PHICH at the 9^(th) subframe2125.

The above embodiment is directed to the case of using the dynamic TDDoperation 1. The difference of the UE operation in the case of using thedynamic TDD operation 2 is described hereinafter.

The UE operation in the case of applying the dynamic TDD operation 1 atsteps 2005, 2010, and 2020 to 2035 is identical with the UE operation inthe case of applying the dynamic TDD operation 2. In the case of usingthe dynamic TDD operation 2, step 2015 is not required.

At step 2040, the UE determines the subframe for receiving PHICHaccording to the following conditions.

[Conditions]

Fixed downlink subframe after at least four subframes since the subframein which PUSCH has been transmitted, subframe appearing first amongfixed special subframes and flexible subframes.

In the embodiment of FIG. 21, UE which has transmitted PUSCH at thethird subframe receives PHICH at the 8^(th) subframe 2130 fulfilling theabove condition.

It may occur that the UE configured for the dynamic TDD operation doesnot recognize the second TDD configuration temporarily. For example,this may be the cases in that the UE is operating in the discontinuousreception period of the subframe carrying the second TDD configurationinformation and the UE suspends receiving downlink signal at a subframefor measurement on other frequencies.

FIG. 22 is a flowchart illustrating an operation taken when the UE whichhas not recognized the second TDD configuration temporarily receives anuplink grant.

Referring to FIG. 22, steps 2205 and 2210 are identical with steps 1605and 1610.

The UE receives an uplink grant at step 2215. For convenience, it isassumed that the subframe at which the PUSCH is transmitted is then^(th) subframe.

The UE determines whether the second TDD configuration information to beapplied to the corresponding timing is received at step 2220. Asdescribed above, the second TDD configuration information is transmittedat a predetermined interval. For example, the second TDD configurationinformation to be applied to the m^(th) time duration is transmitted ina predetermined subframe of the (m−1)^(th) time duration and, when theuplink grant is received at a certain subframe of the m^(th) timeduration, the UE determines whether the corresponding subframe has thesecond TDD configuration information to be applied to the m^(th) timeduration. If so, the procedure goes to step 2225. If not, the goes tostep 2230.

At step 2225, the UE determines the subframe for PUSCH transmission byapplying the first or second TDD configuration considering whether theuplink grant has been received through RAR or PDCCH.

At step 2230, the UE determines whether the uplink grant has beenreceived through RAR or PDCCH. If the uplink grant has been receivedthrough PDCCH, the procedure goes to step 2240 and, otherwise if theuplink grant has been received through RAR, step 2235.

If the procedure goes to step 2240, this means that the UE does notdetermine k although it is supposed to determine k by applying thesecond TDD configuration. Accordingly, the UE does not perform anyinitial transmission even when the uplink grant indicates initialtransmission and does not perform any retransmission even when theuplink grant indicates retransmission. Nevertheless, CURRENT_NB_TX ofrecording the number of transmissions or CURRENT_IRV related toRedundancy Version for use in the next transmission increases normally.

At step 2235, the UE determines whether the preamble triggered thereceived RAR is a dedicated preamble or a random preamble. If it is arandom preamble, the procedure goes to step 2245 and, otherwise if it isa dedicated preamble, step 2250.

If the procedure goes to step 2245, this means that the uplinktransmission corresponding to the RAR uplink grant in the random accessprocedure initiated with the random preamble. The UE determines k1 byapplying the first TDD configuration, even though it does not know thesecond TDD configuration, and has to transmit PUSCH using the uplinktransmission resource allocated in the (n+k1)^(th) subframe (if theuplink delay is set to 0) or the first uplink subframe after the(n+k1)^(th) subframe (if the uplink delay is set to 1).

If the procedure goes to step 2250, this means that the UE has toperform the uplink transmission corresponding to the RAR uplink grant inthe random access procedure initiated with the dedicated preamble.Although the UE has to determine k1 by applying the second TDDconfiguration, since it does not know the second TDD configuration to beapplied to the corresponding time duration, the UE cannot determine k1.The UE ignores the uplink grant, i.e. skips PUSCH transmission using theuplink transmission resource allocated by means of the uplink grant, andstarts the preamble retransmission procedure. That is, the UEretransmits the preamble in the uplink subframe fulfilling apredetermined condition. The predetermined condition is fulfilled by theuplink subframe having the preamble transmission resource which appearsafter at least 4 subframes when the first TDD configuration is applied.

FIG. 23 shows an operation of receiving PHICH at the UE which has notrecognized the second TDD configuration temporarily.

Steps 2305 and 2310 of FIG. 23 are identical with steps 1605 and 1610.

The UE performs PUSCH transmission at step 2315. For convenience, it isassumed that the subframe at which the PUSCH is transmitted is then^(th) subframe.

The UE determines whether the second TDD configuration information to beat the corresponding timing is acquired at step 2320. As describedabove, the second TDD configuration information is transmitted at apredetermined interval. For example, the second TDD configurationinformation to be applied at the m^(th) time duration is transmitted ina predetermined subframe of the (m−1)^(th) time duration and, when theuplink grant is received at a certain subframe of the m^(th) timeduration, the UE determines whether the subframe has the second TDDconfiguration information to be applied to the m^(th) time duration. Ifso, the procedure goes to step 2325. If not, the procedure goes to step2230.

At step 2315, the UE determines the subframe for receiving PHICH byapplying the first or second TDD configuration considering whether theuplink grant triggered the PUSCH transmission has been received throughRAR or PDCCH.

At step 2330, the UE determines whether the uplink grant triggered thePUSCH transmission has been received through RAR or PDCCH. If the uplinkgrant has been received through PDCCH, the procedure goes to step 234and, otherwise if the uplink grant has been received through RAR, theprocedure goes to step 2335.

If the procedure goes to step 2340, this means that although it issupposed to determine the subframe for receiving PHICH by applying thesecond TDD configuration the UE cannot determine the subframe because itdoes not know the second TDD configuration. Accordingly, the UE stopsattempting PHICH reception. Then the UE sets HARQ_FEEDBACK to ACK suchthat non-adaptive retransmission corresponding to the PUSCH does notoccur. Or the UE flushes the buffer of the HARQ process associated withthe PUSCH transmission. The HARQ_FEEDBACK is a parameter for managingthe last HARQ feedback information per HARQ process and it is set toNACK for performing non-adaptive retransmission and ACK for suspendingtransmission until a separate retransmission command is received.Although the HARQ_FEEDBACK has to be set according to the actuallyreceived HARQ feedback, it is set to ACK even though the HARQ feedbackis not received if PHICH is not received due to no information about thesecond TDD configuration.

At step 2335, the UE determines whether the preamble triggered the RARreception is a dedicated preamble or a random preamble. If it is arandom preamble, the procedure goes to step 2345 and, otherwise if it isa dedicated preamble, step 2340.

If the procedure goes to step 2345, this means that the uplink grant hasbeen received through RAR in the random access procedure initiated withthe random preamble and thus the PUSCH has been transmitted.Accordingly, the UE determines k by applying the first TDDconfiguration, although it does not know the second TDD configuration,and receives PHICH at the (n+k)^(th) subframe. FIG. 12 is a blockdiagram illustrating a configuration of the UE to which the presentinvention is applied.

The UE includes a transceiver 1200, a multiplexer/demultiplexer 1205,upper layer processors 1210 and 1215, and a controller 1220. In the caseof transmitting control signals and/or data to the eNB, the UEmultiplexes the controls signals and/or data by means of themultiplexer/demultiplexer 1205 and transmits the multiplexed signal bymeans of the transceiver 1215 under the control of the controller 1220.In the case of receiving signals, the UE receives a physical signal bymeans of the transceiver 1200, demultiplexes the received signal bymeans of the multiplexer/demultiplexer 1205, and delivers thedemultiplexed information to the higher layer processor 1210 and/orcontrol message processor 1215, under the control of the controller1220.

FIG. 13 is a block diagram illustrating a configuration of an eNBaccording to the present invention.

Referring to FIG. 13, the eNB includes a transceiver 1305, a controller1310, a multiplexer/demultiplexer 1320, a control message processor1335, various higher layer processors 1325 and 1330, and a scheduler1315.

The transceiver 1305 transmits data and predetermined control signalsthrough a downlink carrier and receives data and predetermined controlsignals through an uplink carrier. In the case that a plurality ofcarriers are configured, the transceiver 1305 transmits/receives dataand control signals through the plural carriers.

The multiplexer/demultiplexer 1320 is responsible for multiplexing datagenerated by the higher layer processors 1325 and 1330 and the controlmessage processor 1335 or demultiplexing the data received by thetransceiver 1305 to deliver the demultiplexed data to the higher layerprocessors 1325 and 1330, control message processor 1335, or controller1310. The controller 1310 determines whether to apply a band-specificmeasurement gap to a specific UE and whether to include theconfiguration information in the RRCConnectionReconfiguration message.

The control message processor 1335 generates theRRCConnectionReconfiguration to the lower layer according to theinstruction of the controller.

The higher layer processors 1325 and 1330 may be established per UE orper service to process the data generated in association with the userservice such as File Transfer Protocol (FTP) and Voice over InternetProtocol (VoIP) and transfer the processed data to themultiplexer/demultiplexer 1320 or process the data from themultiplexer/demultiplexer 1320 and transfer the processed data to theupper layer service applications.

The scheduler 1315 allocates transmission resource to the UE at anappropriate timing based on the buffer status, channel status, andActive Time of the UE and controls the transceiver 1305 to process thesignals received from and to be transmitted to the UE.

It is to be appreciated that those skilled in the art can change ormodify the embodiments without departing from the technical concept ofthis invention. Accordingly, it should be understood thatabove-described embodiments are essentially for illustrative purposeonly but not in any way for restriction thereto. Thus the scope of theinvention should be determined by the appended claims and their legalequivalents rather than the specification, and various alterations andmodifications within the definition and scope of the claims are includedin the claims.

Although preferred embodiments of the invention have been describedusing specific terms, the specification and drawings are to be regardedin an illustrative rather than a restrictive sense in order to helpunderstand the present invention. It is obvious to those skilled in theart that various modifications and changes can be made thereto withoutdeparting from the broader spirit and scope of the invention.

1-16. (canceled)
 17. A method of a terminal in a communication system,the method comprising: receiving a first time division duplex (TDD)uplink/downlink (UL/DL) configuration from a base station; receivingconfiguration information related to a second TDD UL/DL configurationfrom the base station; receiving downlink control information indicatingthe second TDD configuration from the base station based on the receivedconfiguration information; transmitting, if uplink schedulinginformation is received in a random access response message, a messagecorresponding to the uplink scheduling information to the base stationbased on the first TDD UL/DL configuration; and transmitting, if uplinkscheduling information is received on a physical downlink controlchannel (PDCCH), a message corresponding to the uplink schedulinginformation to the base station based on the second TDD UL/DLconfiguration.